Optoelectronic assemblies are often designed to reduce thermal resistance between high-power devices mounted on the top surface of a substrate and a heat sink coupled to the bottom surface of the substrate.
For example, U.S. Pat. No. 6,936,855, whose disclosure is incorporated herein by reference, describes a bendable light emitting diode (LED) array that includes heat spreaders, dielectric material disposed above each heat spreader, and a bendable electrical interconnection layer disposed above these heat spreaders and electrically insulated from these heat spreaders by the dielectric material. At least one via passes through the dielectric material above each heat spreader, and at least one LED die is disposed above each via.
U.S. Pat. No. 6,156,980, whose disclosure is incorporated herein by reference, describes a circuit structure and method for conducting heat from a power flip chip. Heat is dissipated from a flip chip mounted to a PCB by conducting heat through conductive vias to the opposite surface of the PCB. The flip chip is equipped with two sets of solder bumps, one of which is registered with conductors on the PCB, while the second is registered with a thermal conductor layer on the PCB surface and electrically isolated from the conductors.